The invention relates to a ship drive with a drive engine and directly driven propeller shaft.
A ship drive according to the category is known from DE 196 23 914 A1. This ship drive consists of a drive engine and propeller shaft which is directly connected therewith and provided with a propeller and the thrust of which is taken up by a thrust bearing. For auxiliary and emergency operation the known ship drive has a supplementary drive consisting of an electric engine which is to be operated selectably as a generator or a motor and which is connected with a transmission by way of a clutch. A gearwheel of the transmission surrounds the propeller shaft, which is connected with the gearwheel by way of a flexible coupling. Arranged between transmission and drive engine and on a separate section of the propeller intermediate shaft is a play-free switchable coupling, which is combined with a play-free auxiliary thrust bearing transmitting the propeller thrust. In the case of auxiliary or emergency operation of the ship, this auxiliary thrust bearing is activated, wherein the correspondingly reduced propeller thrust is introduced by way of the auxiliary thrust bearing to a thrust bearing arranged in the drive engine and thus into the ship hull.
One of the significant simplifications in the case of the ship drive according to German patent P 197 29 046.9 consists in replacing, in advantageous manner, the expensive switchable clutch by a rotationally stiff, but axially pliant diaphragm coupling. In that case, the diaphragm coupling is clamped in by one element between a flange of the propeller intermediate shaft and an opposite flange of the thrust shaft. The other element of the diaphragm coupling is fastened to the support collar of the auxiliary thrust bearing. The two elements of the diaphragm coupling are held together by way of cone screw bolts which are arranged to be distributed at the circumference and which are supported in a ring. In normal operation the pressure blocks of the auxiliary thrust bearing are tightened against the flanges of the drive side and the propeller intermediate shaft, so that the full propeller thrust is transmitted by way of this bearing statically into the thrust bearing of the drive engine and can thus be introduced into the ship hull. The diaphragm coupling takes over the torque transmission. The tightening of the pressure blocks is effected by a threaded ring, which at the rear side of the flange of the thrust shaft is arranged thereon and supported against the inwardly disposed surface of a support collar formed in bell shape. The support collar is in turn fixedly connected with the flange at the drive side and journalled on the thrust shaft. In order to be able to actuate the threaded ring, cutouts, which extend through the wall, are provided in the circumferential region of the support collar.
In the case of auxiliary and emergency operation of the ship the screw bolts are withdrawn from the diaphragm coupling, so that a direct connection between propeller intermediate shaft and thrust shaft and thus the drive side no longer exists. According to whether in the case of emergency operation a forward travel or a reverse travel is concerned, the corresponding pressure blocks of the auxiliary thrust bearing come into contact. This contact enables the transmission of the reduced propeller thrust to the thrust bearing arranged in the drive engine. According to the respective level of power to be transmitted in the emergency operation, a pressure oil lubrication is required, or a filling up of the bearing is sufficient. In the former case the appropriate components have channels so that the supplied oil can pass into the region of the pressure blocks and conduct away friction heat from there. In the case of lower power the heat radiation extends over the casing. So that the threaded ring cannot unintentionally rotate in the switched-in setting or the switched-out setting, it is secured by appropriate means, for example pins, wire snaps. Switched-out setting signifies in that case a previous rotation of the threaded ring so that the clamping is cancelled and the pressure blocks have the required play.
A specific disadvantage with this ship drive consists in that a comparatively long time is needed for a switching-in and switching-out of the coupling, which is no longer indulged in by cost-conscious shipping companies.